Shafts of this nature, which have considerable length and a large diameter, are generally divided into a plurality of tubular sections with interposition of a coupling sleeve of substantially the same inner and outer diameters between any two adjoining sections. Similar sleeves, without coupling functions, may also be secured to the free ends of the outermost sections. Each sleeve is rotatably supported in a stationary cylindrical housing, coaxial therewith, by an individual journal bearing carrying a single set of rotary bodies--preferably short cylindrical rollers--along a narrow track between its inner an outer races.
The inner bearing race is conventionally formed by a ring which is press-fitted onto the respective coupling or terminal sleeve. A similar, larger ring is press-fitted into the associated housing to form the outer bearing race.
At the high operating speeds customarily used in such machines the inner bearing race is subjected to large centrifugal forces tending to detach if from its supporting sleeve, thereby impairing the performance of the journal bearing. Furthermore, the machining of the ring to have it fit precisely onto the outer sleeve surface is difficult and correspondingly expensive.